全文获取类型
收费全文 | 121124篇 |
免费 | 8515篇 |
国内免费 | 2054篇 |
专业分类
131693篇 |
出版年
2024年 | 282篇 |
2023年 | 978篇 |
2022年 | 1685篇 |
2021年 | 2968篇 |
2020年 | 2102篇 |
2019年 | 2410篇 |
2018年 | 3731篇 |
2017年 | 3198篇 |
2016年 | 4514篇 |
2015年 | 6345篇 |
2014年 | 6709篇 |
2013年 | 8570篇 |
2012年 | 10134篇 |
2011年 | 9197篇 |
2010年 | 5752篇 |
2009年 | 4660篇 |
2008年 | 6914篇 |
2007年 | 6434篇 |
2006年 | 5860篇 |
2005年 | 5144篇 |
2004年 | 4818篇 |
2003年 | 4378篇 |
2002年 | 4039篇 |
2001年 | 2164篇 |
2000年 | 1946篇 |
1999年 | 1771篇 |
1998年 | 1060篇 |
1997年 | 789篇 |
1996年 | 820篇 |
1995年 | 738篇 |
1994年 | 711篇 |
1993年 | 589篇 |
1992年 | 881篇 |
1991年 | 772篇 |
1990年 | 720篇 |
1989年 | 621篇 |
1988年 | 576篇 |
1987年 | 518篇 |
1986年 | 457篇 |
1985年 | 498篇 |
1984年 | 485篇 |
1983年 | 342篇 |
1982年 | 331篇 |
1981年 | 257篇 |
1980年 | 267篇 |
1979年 | 308篇 |
1978年 | 254篇 |
1975年 | 249篇 |
1974年 | 254篇 |
1973年 | 283篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
82.
M. J. Prol García P. W. D'Alvise L. Gram 《Applied and environmental microbiology》2013,79(17):5414-5417
Quorum sensing (QS) regulates Phaeobacter gallaeciensis antagonism in broth systems; however, we demonstrate here that QS is not important for antagonism in algal cultures. QS mutants reduced Vibrio anguillarum to the same extent as the wild type. Consequently, a combination of probiotic Phaeobacter and QS inhibitors is a feasible strategy for aquaculture disease control. 相似文献
83.
84.
85.
86.
Antonio Jiménez-Escrig Eva Gómez-Ordóñez María Dolores Tenorio Pilar Rupérez 《Journal of applied phycology》2013,25(2):503-512
The edible brown seaweed sugar Kombu (Saccharina latissima) is a good source of dietary fiber (DF) and associated compounds. Besides it presents antioxidant capacity in vitro due to their sulfated polysaccharides and polyphenols. The effect of a DF-rich sugar Kombu diet on biochemical parameters and antioxidant and prebiotic effects in healthy rats was evaluated. Thus, rats were fed either a basal diet or a supplemented one with 10 % sugar Kombu for 4 weeks. Several health-promoting effects were found such as a decrease in triglycerides (TGL) and uric acid (UrA), and an increase in antioxidant status both in serum and cecum. Regarding prebiotic effect, higher cecum weight and total short chain fatty acid (SCFA) content were evidenced in the seaweed-fed group, without significant differences on total bacterial count of feces. Sugar Kombu and sulfated polysaccharides from its DF could be used as functional ingredients for further nutraceutical applications. 相似文献
87.
Nelson Marques John F Araujo Ana Stella F Righini J J Fleury J B F Costa-Neto Maria Clara S Caldas 《Biological Rhythm Research》2013,44(3):343-350
We describe the semen characteristics of a 21-year old “mangalarga” stallion living under natural temperature and photoperiod conditions in São José do Rio Pardo, São Paulo, Brazil (latitude 21°36' S; longitude 46°53' W). The horse fed on natural pasture and a nutritionally balanced feed twice a day (11:00 and 17:00 h). Water and a mineral supplement were available “ad libitum”. Semen was collected for over 36 months (Oct 89-Dec 92) almost daily between 08:00 and 10:00 h by an artificial vagina and evaluated for volume of ejaculate, spermatozoa motility and concentration by standard procedures. Analysis of data from a total of 128-days was performed according to the Fast Fourier Transform Technique (FFT). Statistically significant periods of 7-day were demonstrated for volume, motility, and spermatozoa concentration. Circaseptan rhythms and, particularly, the circannual rhythm (already described in a previous publication) are probably related to ecological diversity and reproductive strategies. 相似文献
88.
89.
Consuelo Sandoval José M. Méndez Rubén Sánchez-Obregón Carmen B. Alpízar 《Biocatalysis and Biotransformation》2013,31(1):36-44
Cultured plant cells from Taxus brevifolia Nutt and Taxus globosa Schltdl were investigated as biocatalysts using exogenous substrates. Production of highly specific metabolites by these species prompted us to analyse their synthetic potential. Whole cells suspensions have the capacity to chemoselectively reduce ethyl acetoacetate to ethyl 3-hydroxybutyrate chemo- and stereoselectively reduce rac-2-benzoylcyclohexanone to (1R, 2S)- and (1S, 2S)-2-hydroxycyclohexylphenylmethanones, and to cyclize N-phthaloyl-L-glutamine to thalidomide. 相似文献
90.
J. Cegoñino J.M. García Aznar D. Palanca B. Seral F. Seral 《Computer methods in biomechanics and biomedical engineering》2013,16(5):245-256
The main objective of this work is the evaluation, by means of the finite element method (FEM) of the mechanical stability and long-term microstructural modifications in bone induced to three different kinds of fractures of the distal femur by three types of implants: the Condyle Plate, the less invasive stabilization system plate (LISS) and the distal femur nail (DFN). The displacement and the stress distributions both in bone and implants and the internal bone remodelling process after fracture and fixation are obtained and analysed by computational simulation. The main conclusions of this work are that distal femoral fractures can be treated correctly with the Condyle Plate, the LISS plate and the DFN. The stresses both in LISS and DFN implant are high especially around the screws. When respect to remodelling, the LISS produces an important resorption in the fractured region, while the other two implants do not strongly modify bone tissue microstructure. 相似文献